Inflammatory mediator release in normal bronchial smooth muscle cells is altered by pregnant maternal and fetal plasma independent of asthma.

Studies have shown that pregnancy can alter the pathophysiology of a pre-existing maternal disease such as asthma. However, the mechanisms that alter maternal asthma during pregnancy are presently unknown. Previous work has demonstrated that human bronchial smooth muscle (BSM) cells produce inflammatory factors in response to nonpregnant, atopic plasma. The aim of this study was to determine whether circulating pregnancy-derived factors in maternal and fetal plasma can stimulate inflammatory mediator release in BSM cells in the presence and absence of maternal asthma. Cultured human BSM cells were exposed to maternal and fetal plasma from normal pregnancies and pregnancies complicated by asthma. Inflammatory mediator release was determined by enzyme-linked immunosorbent assay (ELISA). Both maternal and fetal plasma from asthmatic and nonasthmatic individuals significantly increased production of interleukin (IL)-6 (ANOVA, P<0.001), regulated upon activation, normal T-cell expressed and secreted (RANTES) (ANOVA, P<0.01), and soluble intercellular cell-adhesion molecule-1 (sICAM-1) (ANOVA, P<0.01). There was no difference in inflammatory mediator release in response to asthma and nonasthmatic plasma. Eotaxin release was increased by pregnant asthmatic plasma (ANOVA, P<0.05). The results of this study suggest that circulating pregnancy-related factors can activate asthma-associated mediators in BSM cells. This change in BSM function may be one mechanism that contributes to increased asthma severity during pregnancy.